AU619268B2 - Foaming agent - Google Patents

Description

AUSTRALIA

64926 8 Patent Act C 0 M4 P L E T E S P EC I F I C A T IO0N

(ORIGINAL)

Class Ilit, Class Application Numiber: Lodged: Complete Specification Lodged: Accepted: Pubi ished: Prioritty.* Related Artj nnenjculrnent contains the SeCU~ sW~oc~~ Under Thll by the Super.

411fOLirILlton i .4

I

I APPLICANT'S REF: 563,517 NaMe(S) of Applicant(s): *DO FAA_,INC.

A

'K

Address (es) of Applicant(s): Domtar. House.

395-de Maz'~onneuve,,Blvd West Montr#)a'l

Q<ANADA

YA i L, ti 11 0 -710 -7 Our Address for Service is: PHILLIPS OflMONDE

FITZPATRICK

Patent and Trade Mark Attorneys 367 Collins Streot MELBOURNE, Australia 3000 Complete Specification for the invention entitled; FOAMING AGENT The f0111, 4ing statement is a full description of this invenition, including the best method of per~forming it known to applicant(s): 080 4N i j 2 S2NT 07-17,Q42 filMed now abandondA The invention relates to an improved foaming agent having a greater capacity for producing foam. This invention is particularly directed to such foaming agents to be used in the making of gypsum products a-id to the products so made, to other end uses, for instance, fire fighting foams.

PRIOR ART Samuel Cukier, in C.P. 1,085,880 dated 16 September 1980 and in U.S. 4,156,615, discloses an alkyl ether sulfate having an improved performance for the manufacture of ptoo gypsum, wherein said alkyl ether sulfate is:

CH

3

(CH

2

XCH

2

-(OCH

2

CH

2 )y-OSO3M in which: S" CH 3

(CH

2 )xCH2 is the alkyl group

S(OCH

2

CH

2 )y is the ether group M is the cation (NH 4 or Na) wherein x is between 6 and 8, and has an average value of I 6.5-7.5 and y is between 1.5 and 2.5 (which herein is also referred to as Type A).

It should be noted that: in Cukier's patent the performance is measured on the basis of the stiffening time of the gypsum slurries (Example heat savings (Example 2) and reduced product consumption to achieve similar thermal set times (Example 3).

U.S. 4,678,515 as invented by Green et al discloses surfactants with improved foaming properties by means of 0 n"s mixing about 11 to 33% of alkyl ether sulfates in which x U Sec, 10 to 12 and y 1 to 3.0, with curfactants of Type A as described above to obtain an average x between 6 to 12.

S- 3 In Green et al's patent performance is measured on the basis of the amount of foam and foam stability produced by the surfactants when added to the supernatant liquid of a saturated gypsum solution, as seen in column 2, line 34 of the patent, from which gypsum, which is mainly composed of calcium sulfate, has been removed. by operating in this manner, the foaming tests are conducted in the presence of a constant or "static" amount of Ca ions, which is determined by the solubility product of calcium sulfate.

Alkyl ether sulfate surfactants are sensitive to Ca ions: they react to form the calcium salt of the ether sulfate which may be water insoluble.

0 o0 In a Ca ion "static" system, as that used by oreen et .0 al to conduct the foaming tests, when a free Ca ion reacts with the ether sulfate to form an insoluble surfactant, the reacted Ca ion cannot be replaced by another Ca ion, as governed by the solubilty product because the source of Ca 0 ions, i.e, gypsum, has been removed from the system.

0 09 In the actual manufacturing of gypsum board, the ether 0 sulfate is exposed to a continuous flow of Ca ions, in the sense that for every free Ca ion removed from solution due to reaction with ether sulfate, another Ca ion is supplied by the gypsum material (to maintain constant the solubilty product) which, in turn, may form another insoluble Ca surfactant, and so on.

As a result of this, the foaming profile of an ether sulfate surfactant may be different in a "static) foaming test and in the actual manufacturing of gypsum board, specially if the "static" foaming test is carried-out under conditions in which the surfactant is tested using great amounts of surfactant relative to the amount of free and/or replaceable Ca ions than the foaming agent may encounter during the actual manufacturing of gypsum board.

It should be borne in mind that in the Green et al patent there is not indication of the performance of the foaming agents on the actual manufacturing of gypsum material made from gypsum slurries in terms of foam entrained in finished gypsum, as in the real manufacturing, i.e. when the foaming agent is exposed to a continuous flow of free Ca ions. In fact, Green et al best results are obtained when the foamers are evaluated in "static" foaming tests with large amounts of surfactants, i.e. under excess of foaming agent relative to the "static" amount of Ca ions.

THE INVENTION 4 a 20 Broadly stated, the invention is directed to a foaming agent comprising a blend of alkyl sulfates and alkyl ether sulfates having an improved foaming performance, wherein said aa blend has the general formula: R -(OCHCH -OOM, wherein f= Rx is -4a- forming an alkyl chain selected from at least one member of the group consisting of linear and branched chains, wherein at least 90% of x is between 8 to 10, the average y is from 0.4 to 1.3, and wherein M is a cation producing a water soluble surfactant.

The invention is also directed to an improvement in a method of making gypsum board using a blend of alkyl sulfates and alkyl ether sulfates having the general formula:

I

)0O 00 00 0 04 O 0000 0 S00 0 0 0 0.0

-(OCH

2

CH

2 )Y-OS0 3 M as described above, the improvement comprising mixing with gypsum a catalytic amount of said sulfates, wherein at least 90% of x is b~~-1f said fi "f-rming -a-Tchai i. selected from at least one member of the group consisting of liniear and branched chains, the average y is-bcwz .4rd)l.S And wherein M is a cation producing a water soluble surfactant.

The invention is also directed to a new gypsum product containing the residual foaming agent as defined above. The improved foaming performance can be evidenced, for instance, from Table III and IV on pages 12 and 13.

PREFERRED WAY OF CARRYING OUT THE INVENTION A preferred way of carrying out the invention consists in reacting in a molar ratio in the order of 0.4-1.3:1 and most preferably 0.8:1 ethylene oxide with linear and/or branched fatty alcohols having at least 90%, preferably 98% and more, of 8-10 carbon atoms, in the presence of a catalyst to incorporate the ethylene oxide groups. Typical examples of such catalysts include NaOH and KOH. Once the ethylene oxide groups are incorporated, the ethoxylated fatty alcohols are then sulfated with a sulfating agent and then neutralization is accomplished to obtain directly the new foaming agent.

Typical examples of a cation producing a water soluble surfactant includes sodium, potassium, calcium, magnesium and the lik1e, Cnd preferably ammonium.

The foaming agen4t is preferably diluted with a carrier wherein the foaming agent is the major constituent, i.e. at 6 least 50%. Typical carriers are preferably alcohols having low molecular weight such as methanol, ethanol, propanol.

This foaming agent is particular useful in the making of gypsum board and used in catalytic amounts. Preferably that catalytic amount is 0.03±0.01% per 100 parts of stucco as determined by the (CTFA) method 8-1 of the Cosmetic Toiletry Fragrance Association of Washington, D.C. This foaming agent is generally used for such a purpose in a diluted form such as those described hereinbelow.

The novel product contains a greater foam in gypsum product with respect to the amount on weight basis of foaming agent.

OTHER MEANS OF CARRYING OUT THE INVENTION There are other indirect ways of carrying out the invention such as by blending fatty alcohols with ethoxylated fatty alcohols to obtain the average y of oQMm O-u =o qrYm o'1 bo o-'9 eawee-n 0.4 l-.3and preferably 0G.7- .9followed by sulfation of the blend with a sulfating agent and then neutralizing the mixture, or by reacting fatty alcohols with a s. fating agent neutralizing it and blending this reaction product with an alkyl ether sulfate to obtain the average y qrm 0, Lk N=.0 -S qT-0re\ 0- Dj of beatwen 3.4 1 3 and preferably 7 The following examples will serve to illustrate particular embodiments of the invention.

EXAMPLES 1-6 The foaming agent of Example 1 was prepared by blending 25% of the ethoxylate of Sample A with 75% of a linear fatty alcohol wherein at least 90% of x is--between 6 d and 7 7 having 0 as y value (which we will call Sample E) and then r sulfating the blend.

Y

7 The foaming agent of Example 2 was prepared by blending of Sample E and 50% of the ethoxylate of Sample A and then sulfating the blend.

The foaming agent of Example 3 was prepared by the direct method.

The foaming agent of Example 4 was prepared as in Example 3 but replacing approximately 50% of linear octanol by an equivalent amount of branched ethyl hexanol.

The foaming agent of Example 5 was prepared by blending of Sample E and 75% of the ethoxylate of Sample A and then sulfating the blend.

.oo The foaming agent of Example 6 was prepared by blending o* 50% of the ethoxylate of Example 3 and 50% of the ethoxylate of Sample A and then sulfating the blend.

9 o c THE GYPSUM BLOCK METHOD Using a method simulating the manufacture of gypsum wallboard, gypsum blocks were made as follows: 1. The foaming agent is diluted in water to obtain a 9 4 o" solution having a concentration of 0.50% for a 100% active 4 9 basis alkyl ether sulfate wherein at least 90% of X is Oo 'tetw~nn 6 and and the average y is as shown in Table 1.

2. The following blend is then prepared: 10g of above solution; 145g of water; 200g of stucco; and about 2g of additives normally used in the manufacturing of wallboard, such as binders, accelerators, etc.

3. The above blend is allowed to stand for 30 sec. and then mixed for 15 sec. in a Hamilton Beach Mixer.

4. The resulting slurry is poured into plastic moulds.

c The blocks are then dried at 43"C for 48 hrs.

U\ c 71 5. The performance of the foamers is measured in terrs of 8 foam entrained in the blocks. This value is obtained via a simple mathematical calculation which considers the weigh of the blocks before and after drying and the density of stucco. The foam of the gypsum blocks is shown in Table 1, Examples 1-6.

The same was carried out according to the prior art: Sample A using Cukier's patent.

Samples C and D using amongs the best species of Table 2 of Green et al patents i.e. Material Tested I and IV of cM C 'rrs-po LkA ho "L T oa'o\e.. 2L Table 2 Column 2\of the patent.

Results are shown in Table 2, as Samples A, C and D.

TABLE 1 y average volume foam Ether in gypsum Example Grou_ Blocks 1 0.4 25.6 2 0.8 26.4 3 0.8 26.4 4 0.8 26.0 1.3 26.1 6 1.3 25.8 N 4 e Sec. c 77

/VJ

I -r 9 4 4 4 44 4i 4 4 4 4 4 TABLE 2 x value y average foam in Sample (Alkyl group) (Ether group) qypsum blocks A) cukier's about 50% by 2.2 24.4 patent weight of x-8 and 50% of x=\0 B) about 50% by 3.0 23.0 weight of x=q and 50% of x=lo C) As per Table 2, Example I of Green et al's patent a Tixture of surfactant of Sample A and 12.5% of surfactant having about 67% of x=l1.Z with an average y value of 1.2 22.5 D) As per Table 2, Example IV of Green et al's a mixture of 75% of Sample B and 25% of surfactant having about 67% of x=lZ and 33% of x 14 with an average y value of of 3.0 19.9 The performance of the foaming agents as can be clearly seen, are directly assessed by the actual making of gypsum products, i.e. blocks, and measuring in the gypsum blocks, the volume of foam" which relates to the amount of air entrained in the blocks. This is contrary to the prior art that use arbitrary and indirect methods. According to this test in the making of the gypsum blocks containing the foaming agent left as residuum, the higher the volume of foam the lighter the block and, therefore, the better the performance of the foamer.

10 As can be seen, Example 1 of Green et al produces a gypsum block having 22.5% volume foam (our sample C).

Example IV produces a gypsum block having 19.9% volume foam (our sample Cukier's product yields a gypsum block having 24.4% volume foam, as compared to applicant's product of 25.8 to 26.4%. This means substantial improvement of applicant's product and particularly improvement of 10-25% over the products made according to the Green et al's teaching. No foaming agent is taught in the prior art which shows the volume foam in gypsum blocks that is equal to those shown in Examples 1-6. It is clear that foaming o 00 ",to agents comprising a blend of alkyl ether sulfates as oooe' described in Examples 1 to 5 have substantial improved o° d* foaming performance.

Such a result cannot be obtained when following Green a o a et al's patent (19.9-22.5%) an even when following Cukier's patent.

Applicant has also determined the distribution ratio of d" the oxyethylene oligomers of the foaming agents by High 4 40 d Performance Liquid Chromotography

(HPLC).

aus CH 3

(CH

2 )xCH2-(OCH 2

CH

2 )y-OH y=o 2 CH 3 (CH2)yCH2-(OCH 2

CH

2 )y-OH y=n n 0, 1, 2, 3, 4, 5, 12 The denominator represents the total oligomeric content.

Results are shown in Table III in weight and Table IV in mole, where a Sample E when y=0 and a new Sample F when Vy3 were introduced to clearly demonstrate applicant's invention.

1- 11 As seen herein below, the distribution ratio of the oligomers is an important characteristic of the foaming agents since the distribution affects both the sensitivity to Ca ions and the intrinsic foaming performance of the foaming agents.

0 10 B a 906 0 4 9 4 04 4 e h 0 4, 4 44 66D 9 40 9 f 44 4 0« 444, 44 4 a (r 4 4 4 *0 44 4 4 0 °44 44Lr a a aQ C C a C- 12 TABLE III Average y (Ether Example. Group) 1 0.4 2 0.8 3/4 0-8 1.3 6 1.3 samples A* 2-2 B 0 F 3.0 *Cukier's patent I roam Gyp-SuM Blocks 25.6 26.4 26.4 26.1 25.8 24.4 23.2 23.0 0 78.9 57.8 40.5 36.6 27.0 15.5 100.0 15.1 Distribution of 1 2 3.5 3.6 7.0 7.1 21.7 15.2 10.5 10.6 17.8 14.7 oxyet ene 3 4 3.5 3.0 7.0 6.0 9.7 5.4 10.6 9.0 11.9 8.7 oligomers 5 2.2 4.4 3.0 6.5 5.8 8.7 10.7 weight) (0-5) (94.6) (88.3) (95.5) (83.8) (86.9) (78.5) (100) (60.4) 6 1.8 3.5 1.8 5.2 4.4 7-12 3.6 7.2 2.7 10.9 8.7 14.0 5.2 14.2 7. 8 14.1 10.4 12.0 11.2 7.0 14.5 9.8 29.8 04S a .09 0 OS a 0000 a 0 a 13 TABLE IV Example 3/4 6 Samples

A

E

F'

Average y (Ether Group) 0.4 0.8 0.8 1.3 1-3 %Foam Gypsum Blocks 25.6 26.4 26.4 26.1 25-8, 0 81.7 63.4 52.8 45.0 39.8 26,7 100.0 21.4 Distribution of oxvethvyLene Olictoiners mole) 1 4.6 9 2 21.7 13.9 20.1 2 3.8 7.6 12.3 11.4 13.8 3 3.2 6.4 6.6 9,.6 9-7 (0-3) (93.3) (86.6) (93.4) (79.9) (83 .4) 4 2.3 4.6 3.2 7.0 6.2 9.3 11.2 5 1.5 3.0 1.6 4.5 3.8 6.0 9.4 6-12 2.9 5.8 1.8 8.6 6.6 11.5 26.2 2.2 0 3.0 24.4 23.2 23.0 18.5 15.2 12.8 (73.2) (100) 8.9 10.8 12.1 (53.2) I -7, 14 It is clear from Table III that best performance in foam gypsum blocks is when on a weight percentage distribution of the oxyethylene oligomers, the oligomeric species in which y=o is between from 78.9 to 27% and the sum of oligomeric species from y=o to 5 is from 94.6 to 83.8% of the total oligomeric content.

It is also clear from Table IV that the mole must be for y the sum of oligomers from 0-3 of from 93.3 to 79.9%.

It is aljo clear that applicant's invention yields a foaming agent having improved foaming performance. The foam in the gypsum block as made herein, having at least 25.6% foam as compared against 19.9 22.5 for Green et al and 24.4 for Cukier's patent according to the above test.

In summary two criteria are of the outmost importance to produce a foaming agent having improved foaming performance in the making of gypsum panels; the carbon length of the alkyl group and the degree of Sethoxylation.

The alkyl group is determined by x, and ideally x should be between q and to. However since the foaming agents are usually made from industrial grade fatty alcohols of mixed carbon lengths, it is from a practical purpose acceptable to have at least 90%, but preferably 98% and more, of said x between e and 10. Other carbon lengths for which x is not between i andlO, particularly those greater than lo are detrimental and inhibit the foaming properties, since in the presence of gypsum products, when y is low the sulfates having x greater than \o form a water insoluble product with gypsum that precipitates out of he water, and as it precipitates out, additional amounts of tie water soluble foaming agent react With additional amounts of the gypsum products to cause further precipitations, and thereby

N

6<'o 1 r 15 to that extent reducing the effectiveness of the blend as a "oaming agent. This problem increases as the length of x increases, (over x=10). This problem is effectively evaluated only when the foaming agent for gypsum products is evaluated in situ with the gypsum products (the CaS04 reacting). Any simulation with a clear solution of CaSO 4 does not give the concentration and equilibrium in production lines.

The average y must be between 0,4 and 1.3 as illustrated in Table III and IV.

Alkyl ether sulfates are sensitive to Ca ions, they may

S

s react to form the calcium salt of the ether sulfate which depending upon the length of the alkyl group and the I I degree of ethoxylation may be water insoluble, and thereby may produce low foamers.

If we go back to prior art, Green at al patent is based Son their claim that enhanced foaming performance is obtained when ether sulfates having an alkyl group in which x is 1 to IL. are added to ether sulfates in which x4 to\Q.

According to Green, "this is quite surprising since compounds in which x-12 to 14 are poor foam generators compared to their homologs in which x=8 tolo" (column 2, lines 19-22). This foam enhancement is based on foaming tests conducted with saturated gypsum solutions from which gypsumi has been removed before the foaming test is done: our application shows that the ether sulfates covered by Green are inferior to our foamers when their performance is i measured not in foaming tests but in the making of gypsum ,4 j K blocks using recipes typical of gypsum board manufacturing, p< as in the real life. This is clearly stated on Table 2.

I

I

1 I 16 Most important is that our patent application is pointing away from Green et al regarding the composition of the alkyl group. In Green et al patented foamers, the content of the alkyl group in which x=8 toJO must be 89% maximum and 67% minimum, and the rest must be x=12 to 1.

(column 6, lines 53 to 60). We teach the opposite, i.e., the content of the alkyl group in which x= tool must be minimum.

This is a key and a very clear difference: for Green, when a minimum of 11% of a foamer having x=1L to 1L is added to a foamer having x= to the result is a product with enhanced foaming performance. For us, the result is the ol opposite, i.e. inferior performance. As a result, what for 0 09 o0 ao Green is a must (ie, addition of at least 11% of ether 09 9 a sulfates in which x=12 to 14 for applicant is something to be totally avoided (ie, 10% is the most not the least which is tolerable for x other than 8 tolo) The degree of ethoxylation or y value of the ether group is also very important because the sensitivity of the 09 foaming agents to thb, Ca ions and its intrinsic foaming profile is also affected by the value of y: As the y value increases, the sensitivity of tho foaming agents to the Ca ions decreases, but its intrinsic foaming characteristic that is of the essence, also decreasesX Therefore, finding the right balance between low ion sensitivity and high foaming characteristics, the yr value is key in a foaming agents intended for wallboard manufacturing. Cukier patent excludes foamers in which the y value is less than SSe. 1.5. We are teaching a y value between 0.4 and 1.3, i.e.

completely ifferent to Cukier's range.

A 0/ completely different to Cukier s range.

S. 17- The reason for this difference is clearly shown in our Tables III and IV. Sample A is the core of Cukier's patent (y value of Sample E is outside Cukier's patent (and Green) since y=0. Our exainpls 1, 2, and 4 were prepared by blending appropriate proportions of samples A and E. In K other words, the blending of Cukier's product with an inferior foamer resulted in a synergistic effect, since the blends were superior to the individual products. This is clearly illustrated in Tables III and IV.

Having described the invention, modifications will be evident to those skilled in the art without departing from the spirit of the invention, as defined in the appended ,claims.

t t I I 1, i

Claims (10)

1. A foaming agent comprising a blend of alkyl sulfates and alkyl ether sulfates having an improved foaming performance, wherein said blend has a general formula: R (OCH 2 CH 2 )yOSO 3 M, said Rx forming an alkyl chain selected from at least one member of the group consisting of linear and branched chains wherein at least 90% of x is between 8 and 10, the average y is from 0.4 to 1.3, and wherein M is a cation producing a water soluble surfactant.

2. A foaming agent as defined in claim 1 wherein at least 98% of said x is from 8 to 15 3. A foaming agent as defined in claim 1 or 2 wherein, on a weight percent distributior, of the oxyethylene oligomers, the oligomeric species in which y=o is between from 78.9 to 27% and the sum of oligomeric species from y=o to 5 is from I, 94.6 to 83.8% of the total oligomeric content.

4. A foaming agent as defined in any one of claims 1 to 3 t wherein said average y is from 0.7 to 0.9. A foaming agent as defined in any one of the preceding claims wherein M is selected from the group consisting of ammonium, sodium, potassium, calcium and magnesium.

6. A foaming agent as defined in any one of the preceding claims being an ammonium alkyl ether sulfate.

7. A foaming ageit as defined in claim 1 wherein on a mole percent distribution of the oxyethylene oligomers, the sum of oligomers from y=o to 3 is from 93.3 to 79.9% of the total oligomeric content.

8. A foaming agent as defined in any one of the preceding claims wherein said R is a linear chain. Sh 9. A foaming agent as defined in any one of the preceding 18 claims wherein the foam in gypsum blocks, using the gypsum block method, is at least 25.6%. A foaming agent as defined in any one of the preceding claims being diluted with a carrier, said foaming agent being the major constituent.

11. A foaming agent as defined in claim 10 wherein said carrier is a member selected from the group consisting of low molecular weight alcohols.

12. A method of making gypsum board using an alkyl ether q0 sulfate having the formulation: R -(OCH 2 CH 2 -OXO3M wherein R and x are as x 2 2 y 3 defined in claim 1, the improvement comprising mixing with I gypsum a catalytic amount of the product of any one of claims 1 to 11.

13. A method as defined in claim 12 wherein said catalytic 20 amount is 0.03% 0.01 per 100 parts of stucco on finished j t' product. •i 14. A method as defined in claim 12 or 13 wherein said i catalytic amount is added in the form of foaming agent diluted in a carrier, said foaming agent being the major constituent. An improved gypsum product containing the foaming agent as defined in any one of claims 1 to 11 left as a residuum.

16. A foaming agent, as claimed in claim 1, substantially as hereinbefore described with reference to any one of the examples. DATED: 24 October, 1991 PHILLIPS ORMONDE FITZPATRICK Attorneys for: STEPAN CANADA, INC. 3 49 41N WDN 19 ,L